I had to Google this, and apparently they're legs.

But why?

At first, science seemed to be saying "they're designed to do leg things rather than arm things", and I'm like... "Designed? So you're saying science believes in God?"

To which, science replied, "Well... They do leg functions rather than arm functions the majority of the time".

"Alright science, say that's true. What if I broke a bear's back legs, and he spent the rest of his life in a wheelchair..."

"Wait, why would the bear be in a--" "Hush, science. His forelegs would be doing arm functions most of the time, then, yeah? Does that mean they've... Become arms?"

And this is why the second amendment is so important.